Topic: DT250 no spark

[CBGhia]

Hey guys, I am doing some work on a buddies DT250.  I don't know 2 stroke wiring very well.  Now, this has a magneto and there is a black wire that runs from the points up to the coil.  Now, the kill switch just grounds this wire out to stop the bike, but it is grounded now and I don't know why.  The guy said it was running when he dropped it off at my place, but the throttle cable was jacked so I never saw it run. 
The wire going to the coil should not be grounded, right?  You have to pull the magneto to get to the points, and I don't have the right tool.  I thought it best to ask before ripping stuff apart. 

[MoMo]

disconnect the ignition wire at the coil and put one end of an ohmeter on it and the other to ground, rotate the magneto and check if the meter reads continuity when closed and infinity when open.  If my recollection is good the points are adjusted through a slot in the mag.  Also, it is a good idea to use a point file along with electronic cleaner and air to clean the points...Larry

[CBGhia]

I checked the gap, which seemed small, but was opening. But when I hooked up my noise box, the tone never changes.  I opened the gap more, and the tone still never changes. So, the points are grounded out.  What a pain.

[strynboen]

often it shorts hvere the Black vire konnekts to breaker
..it it are turned,a bit  and kontakt metal or ground..it shorts all aut.
as long the breaker is in closed posision..it are shorted to ground..but vhen it opens it vill read the kondensators kapasitet..so still a kind of short-0,22 mikrofarad..and if the vires is konnekted to the high pover coil..it have a heigh ohm reading...so take the Black vire aut of hareness,, to thek

.there is often a kondensator in game too..if there are a breaker..and it can give falce readings at the meter..so diskonnekt all vires to thek for shorts.

.all Yamahas use the same metric thredet puller..so somone have one for shure..its a fine metric therds..m 30 #1..or somthing like ..

the never types have pick up ignisions..and like to burn up the coil for the cdi box/ignision coil..

[CBGhia]

Yeah, I pulled the connection from the rest of the harness.  I traced the short loom and I cannot see anyplace where that wire could ground out.  It has to be in the area around the points/condenser.  Just need to pull the mag.

[MoMo]

Yeah, I pulled the connection from the rest of the harness.  I traced the short loom and I cannot see anyplace where that wire could ground out.  It has to be in the area around the points/condenser.  Just need to pull the mag.

there is a special puller, can't beat this price.  Sure quality is marginal but for a one time or seldom use it should be fine


http://www.ebay.com/itm/Flywheel-Puller-Motorcycles-1968-2014-Honda-Kawasaki-Suzuki-Yamaha-/291496416679?fits=Make%3AYamaha&hash=item43de8a55a7&vxp=mtr

[CBGhia]

Ok guys,  I pulled the flywheel.  The points are fine, but the condenser is grounding out.  There are 3 wires coming from it.  I melted the solder and the grounded wire is going to the coil seen in the diagram below.  The one on the left is linked to the bigger one on the right.  It seems to be grounded at the top, where a ring connector goes to the bolt holding it down.  Should the coils here be reading a ground?

[strynboen]

one end of the coil starts at a ground...

..your have theis special koupled coils..there are  some 100 Windings..in the first coil vho helps the "real" coil be fired up....it vas used on erly jap bikes..but vas to kosty..later modells use a one coil..system

if it gives problem..the konnektion vire can be cut..and put direkt to ground.

.it can funktion fine vitaut the ekstra vindings in the help coil..vho also holds the light/loading.. vindings

[CBGhia]

Got it all sorted out.  The issue was a short caused by a pinched wire.  My fault.  Thanks for the help.